The [disabled by default] custom heartbeat included in Meteor's server
does not end connections when they are considered unhealthy/stale, which
deviates a bit from the default implementation. See:
https://github.com/bigbluebutton/bigbluebutton/pull/11486.
This commit includes a call to the default heartbeat termination timeout
so sockets are correctly cleaned up when the custom heartbeat is
activated. It also adds a customHeartbeatUseDataFrames config to allow
controlling whether the custom heartbeat should use WS data frames as
valid heartbeats as well - this should only be useful for
testing/debugging purposes and the default behavior (true) is
maintained.
As a side note: this change spun off from an investigation where some
problematic networks were triggering periodic client re-connects due to
the default heartbeat failing. Investigation points to the control
frames being put alongside fragmented WS data frames and the server side
failing to recognize the former - which means pong frames would be missed and
the health check would fail. Since the default heartbeat _does not_
account for data frame traffic (eg DDP payloads), it would shut down the
client's WS even though it was healthy.
The custom heartbeat _does_ account for data frames, which mitigates
that scenario and prevents unecessary reconnections.
This is an initial, experimental implementation of the feature proposed in
https://github.com/bigbluebutton/bigbluebutton/issues/14021.
The intention is to phase out the explicit listen only mode with two
overarching goals:
- Reduce UX friction and increase familiarity: the existence of a separate
listen only mode is a source of confusion for the majority of users
Reduce average server-side CPU usage while also making it possible for
having full audio-only meetings.
The proof-of-concept works based on the assumption that a "many
concurrent active talkers" scenario is both rare and not useful. With
that in mind, this including two server-side triggers:
- On microphone inactivity (currently mute action that is sustained for
4 seconds, configurable): FreeSWITCH channels are held (which translates
to much lower CPU usage, virtually 0%). Receiving channels are switched,
server side, to a listening mode (SFU, mediasoup).
* This required an extension to mediasoup two allow re-assigning producers
to already established consumers. No re-negotiation is done.
- On microphone activity (currently unmute action, immediate):
FreeSWITCH channels are unheld, listening mode is deactivated and the
mute state is updated accordingly (in this order).
This is *off by default*. It needs to be enabled in two places:
- `/etc/bigbluebutton/bbb-webrtc-sfu/production.yml` ->
`transparentListenOnly: true`
- End users:
* Server wide: `/etc/bigbluebutton/bbb-html5.yml` ->
`public.media.transparentListenOnly: true`
* Per user: `userdata-bbb_transparent_listen_only=true`
